Oathsworn
by GrandLeviathan
Summary: Fate is not stagnant; it is a constantly-shifting tide that changes with the slightest of breezes, ever-moving and unrelenting. All it takes to avert ones fate, is the will of one determined soul. A determined soul armed with torpedoes, that is. [AU/Canon Divergence]
1. Chapter 1: Divergence

**Oathsworn**

_I, U-556, hereby declare before Neptune, Lord over oceans, seas, lakes, rivers, brooks, ponds, and rivulets,_

_that I will provide any desired assistance to my ally and Lord, Battleship Bismarck,_

_at any place on the water, under water, on land, or in the air._

_Signed: U-556, Parzival of The Seas._

_At the bottom, U-556 had made a drawing of herself towing her Lord Bismarck back to port._

_..._

_''I'm getting closer to the source of the signal... could all this wreckage be...?''_

_Panic shot through her._

_''Gods preserve us! Lord Bismarck must be in trouble!''_

_So foreign, so icy cold..._

_''Let's ride! All ahead full! Chaaaaaarge!''_

_Why did her rudders feel so heavy?_

_''Please hold on, Lord Bismarck!''_

_The familiar depths of the sea, so dark that light struggled to penetrate this deep..._

_''Hold on, I'm coming to save you!''_

_...since when did they feel so unwelcoming?_

_''...Lord Bismarck?''_

''Wake up.''

U-556 jolted, eyes snapping open – only to cringe them shut as the bright morning sun greeted her, piercing in its intensity. The only mercy was the person standing before her, casting a shadow over her and dimming the light, if only slightly.

Her eyes adjusted enough for her to open them, revealing her sister standing before her – U-557. The sleepy-looking submarine seemed even groggier than usual, the bags under her eyes becoming more prominent in the sunlight. She was already dressed in her combat attire, her rigging not manifested but clearly ready to whenever she needed it.

''Sis...?'' U-556 groaned sluggishly, slowly sitting up – idly noting she was still laying under the oak tree that sat on the edge of the port. She _had _been waiting to greet Bismarck when she returned, but given it was suddenly morning she must've fallen asleep.

''Time to sortie.'' U-557 explained tiredly. ''Higher-ups say there's a large merchant fleet scheduled to pass through near Brest. They want us to do our job and sink some of them.''

''Mn~'' U-556 groaned, stretching her arms above her head, blue hair messy from sleeping. ''I was hoping Lord Bismarck would be back by now... guess I'll have to greet her when we get back...''

Her sister only mumbled something incoherent, walking away in search of coffee – barely remembering to tell U-556 when they were leaving. However as silence once again descended on the blue-haired submarine, the remnants of her strange dream haunted the edges of her mind, leaving a pit in her stomach.

''Lord Bismarck...''

It was foolish. Bismarck was amongst the strongest, if not _the _strongest ship of the Ironblood. She embodied their ideals, their strength, their heart and soul. She was worth an entire fleet of Royal Navy ships. She guided the hand of the God of War, and directed the wrath of Neptune. It was stupid to think she could be sunk. Idiotic.

''Hah... I better get something to eat...''

And yet, she couldn't shake off the lingering unease, nor the icy fear that gripped her heart.

X-x-X

The mission was fairly simple. Merchant-sinking always was; you swam near, shot a torpedo, then got the hell out of there before their escorts caught up with you.

_'High Command wasn't kidding...' _U-556 thought quietly to herself, the depths of the ocean concealing her, U-557 and U-81 from any boats above. _'There's a lot more ships than usual... what're they planning...?'_

She felt uneasy at the prospect, but it was nothing compared to the worry she felt. Ever since she woke up she had been oddly restless, the strange dream haunting her every waking moment. It was hard to forget the vivid panic she felt, especially down here in the ocean where you had nothing to do but stare at empty blackness. She couldn't even communicate with her sisters without having to resurface, leaving them in near-complete silence.

Idly U-556 checked her reserves, taking note of her remaining supplies. Around a dozen torpedoes remaining, and a small metal capsule no bigger than her forearm.

She had ended up taking more torpedoes than usual from storage, earning a dressing-down from U-81 about hoarding resources. Even U-557 seemed troubled by her unusually large amount of torpedoes – after all, both of them liked to go fast so they could get back home quicker. Carrying more torpedoes would only slow her down. And yet she felt a desperate, instinctual need to bring more with her, and after some arguing was allowed to.

Hell, the only reason U-81 was even _with _them was because U-556 specifically asked her to. The pink-haired submarine had been against it at first, until U-556 called in a favour. Oaths were important in their world – they were more than a binding formed by words, they were a binding of honour. To break an oath was of the highest disgrace a person could commit.

At least in the Ironblood. For the Royal Navy it was probably something to do with tea.

A tapping on her shoulder drew her attention, glancing to her right. U-81 jerked her finger upwards, tapping her nose for emphasis. U-556 took the hint, nodding and beginning her ascent, dimly hearing her sisters following after her. A splash of water followed her wake as she resurfaced, the water rippling around her.

Two identical splashes reached her ears as U-557 and U-81 popped out the water next to her, the dull humming of their rudders filling the quiet ocean. They were so far away from land that the ocean stretched in all directions, the darkening sky painting the sea a pretty purple hue like the darkest of amethysts.

''How's your ammo and armour?'' U-81 asked pointedly, glancing over at the two girls.

''Seven torpedoes.'' U-557 replied lazily. ''I took two depth chargers; my rudder is a little shaky, but it'll hold.''

''I've got... um, fourteen.'' U-556 added. ''One of the ships hit me with a torpedo; I think I've got a leak somewhere, but it should be fine! For now, at least...''

''Hn. I'm down to five torpedoes.'' U-81 noted calculatingly. ''It's best we head back now. We still have plenty of ammo, but I'm not confident in our armour holding up against anym-''

The pink-haired submarine's words were silenced as a low beeping filled their ears. One that came from their riggings.

''Huh...?'' U-557 squinted at the readings, listening to the Morse code message.

Three quick beeps followed by three long ones, then three quick ones. A pause, then it repeated.

''...S.O.S?'' U-81 frowned, glancing ahead. ''It's coming from ten miles north of us... one of ours?''

''I don't know... should we...?''

U-556 stared at her own rigging, listening as the message repeated over and over.

Her dream flashed in her mind – the bitter coldness of the depths, the crushing feeling of hopelessness and despair, the heart-wrenching longing. The way she couldn't breathe even though she should've had oxygen. The way the abyss felt so evil and hungry, like the open maw of a beast.

Most of all, she remembered the sight of Bismarck slowly sinking into the depths.

''Let's check it out.''

''Huh? You sure?'' U-81 frowned at the blue-haired submarine. ''We don't wanna get caught-''

''Please. Trust me on this.''

''...fine. Lead the way.''

X-x-X

''It's over, Bismarck!''

In response the Battleship unleashed another salvo of shells, her cannons booming as they lit up the evening sky. Her body ached. Her mind was hazy. Whatever power the Siren had attempted to give her had sapped her of her strength, leaving her barely able to stand under her own weight. If she hadn't self-destructed her right turrets she would've collapsed under the strain.

Pillars of water erupted to her right as another barrage of shells flew past her, narrowly missing her remaining turrets. She steadied herself and fired another salvo towards King George V, but the shots went wide and missed by a large margin – something the Royal Navy clearly noticed, slowly closing in on her. Increasing their chances of hitting her.

''Tch...'' Bismarck grit her teeth, stubbornly ignoring the call of the ocean. If she was to go down, she would fight to her last breath. Even as her body broke and her mind crumbled, as long as she stood, she would never surrender.

She gazed at her right arm, grimacing at the bloody mess it was. Her cannons were not the only thing harmed by her self-destruction attempt.

Movement caught her attention and her gaze snapped forth, locking onto King George V and meeting her eyes. The blonde woman raised her cannons, the shells reloading with almost-chilling slowness. From this distance, it would take a miracle for her to miss. And both of them knew it.

Bismarck didn't close her eyes, awaiting her fate. She would face death with her eyes wide open. And because of that she noticed the torpedoes a full second before George did.

_BOOM!_

King George V's cry of surprise was music to her ears, but that wasn't her concern in that instant. Instead it was the three waves of torpedoes that passed by her with unfaltering accuracy, striking several Royal Navy ships and spreading panic throughout the fleet as they scrambled their sonar and anti-submarine countermeasures. Something that would easily take half a minute.

Suddenly the water beside her bubbled, before a familiar face popped out. U-556.

''Lord Bismarck!'' U-556 smiled brightly, only for her expression to falter. ''Y-You're injured...''

''Why are you here?'' Bismarck asked in a strained voice, her eyes darting between the adoring submarine and the enemy fleet.

Every second counted. It would only be a short while before the Royal Navy turned their ire towards the submarine. Something Bismarck would not allow.

''W-We were responding to a distress signal, coming from you...''

_'Distress signal...?' _Bismarck thought, blinking in confusion before it hit her – the one she activated when Ark Royal damaged her rudder. One that she had forgotten to deactivate when she realised her fate was inevitable. _'Scheiße...'_

''You must leave.'' The Battleship stated firmly, struggling to not let her own weakness show.

U-556 looked aghast. ''I-I can't do that! I promised-''

''My fate is sealed, U-556.'' Bismarck interrupted matter-of-factly, grunting as she straightened up. ''Leave while you can. For I fear the wrath of the Royal Navy may descend upon you and your sisters, if you do not leave with haste.''

''B-But...'' U-556 hesitated, looking at the Royal Navy task force – U-81 doing a marvellous job of distracting them, landing a critical blow to Ark Royal and further spreading panic.

The submarine looked up at Bismarck, pink eyes wide with fearful concern.

''Who w-will I serve, if you're not here, Lord Bismarck...?''

The Battleship paused at that, a note of hesitation filling her weary body. She wanted to tell U-556 that she could find someone else, someone also worthy of her adoration. Perhaps Tirpitz would be worthy of such an honour, or maybe even Prinz Eugen. While the Ironblood lacked the sheer numbers of the Royal Navy, they still had many ships of their own. Surely there was someone out there for her.

And yet, as she stared into the submarine's pink eyes, she realised the folly of such a statement. U-556 didn't _want_ another Lord, another figure to look up to and chase praise from. She didn't _want _to find another Battleship to protect and serve. She wanted only Bismarck.

Something warm fluttered through her heart, but Bismarck ignored it for the time being.

''...I can't.'' Bismarck muttered reluctantly, looking down – more specifically, at her bleeding ankles. ''Ark Royal damaged by rudders. Any attempt to sail away will only result in me going in circles.''

To her surprise, U-556 didn't seem discouraged. Quite the opposite.

''Don't worry! I came prepared!'' The eager submarine replied, snatching a metal capsule off of her rigging and unscrewing the lid – and from inside came an Elite Management Team, a small group of yellow chicks used for emergency repairs. And were in very short supply at the moment.

Before Bismarck could even question if U-556 got permission, the chicks went to work – hopping down onto the surface of the water and running over to Bismarck's heels, wielding miniature wrenches or screwdrivers. They went to work with a unified chirp, working their magic and quickly healing Bismarck's injuries as best as time would allow.

Suddenly a shell whizzed past the two, striking the water and erupting into a pillar of seawater. Bismarck's gaze darted back towards the Royal Navy forces, a grimace marring her face as she caught sight of several anti-submarine planes taking off. More troubling was the fact they had recovered from the ambush, visibly steeling themselves – the Destroyers and Light Cruisers rearming themselves with depth charges.

''Bismarck!'' King George V called, growling as she realigned her guns.

''Hey! Back off!'' U-556 shouted, glaring fiercely at the enemy Battleship and raising her own, far smaller Destroyer-class gun. ''Eat this!''

Bismarck's eyes widened as the submarine fired... and _sailed directly towards the enemy. _The action easily drew the attention, and ire, of several Royal Navy ships – not least King George V herself. Submarines were assassins – they attacked and avoided getting hit. And because of that, they lacked the armour most surface ships had.

A single Battleship shell would be enough to take her down. Two would be enough to outright kill her. Three, and there'd be nothing left.

''Take thi- wah!'' U-556 ducked, narrowly avoiding a shell from Rodney. ''Aah! W-Wolfpack formation B!''

The blue-haired submarine dived, holding her breath and disappearing beneath the waves – before several depth charges lit the water alight with flashes of orange and gold. For a moment there was silence – before three torpedoes struck the right-side of the fleet, exploding around Dorsetshire and eliciting a pained cry from the woman, drawing her allies' attention.

U-81 and U-556 resurfaced to the left of the fleet, opening fire with their small-arms guns and inflicting minor damage to Rodney – doing little more than make her wince, the shells straining to damage her. Even in humanoid form she was still a Battleship, and held the armour of one.

Both submarines dived, but not before firing several torpedoes – forcing Rodney and several others to carefully evade them, lest they take further damage than necessary. A distraction that bought the submarines enough time to break away,

Bismarck's lips thinned. The urge to fire at King George's exposed side was tempting. Very tempting, but she knew what the three submarines were doing; simple distractions. Using their enemies' empathy against them, making them focus their attention on their own comrades and themselves, rather than Bismarck – and giving the little chicks enough time to heal her rudders.

She felt one of the aforementioned yellow chicks tap her shin, and when she looked down she found them standing in a small semi-circle around her – her ankles healed of their wounds, though the blood staining her boots remained. A spark of grim satisfaction filled her as she subtly surfed across the waves, and this time she didn't feel like she would veer off-course.

With renewed confidence she raised her remaining guns, and fired.

''G-_Gah!_''

For the first time in ages, Bismarck smirked. Perhaps it was the rush of near-death adrenaline running through her, but King George's gasp of pain was incredibly satisfying. It didn't hurt that her shells had ended up blowing apart one of King George's turrets, detonating the ammunition within and burning away part of the Battleship's formerly-pristine uniform.

Water bubbled next to her before U-556 resurfaced alongside U-81 and U-557.

The three submarines were in relatively good shape, considering the circumstances, but they weren't free of wounds. U-557 was bleeding from a wound on her shoulder and blood freely ran down her forehead, blinding her right eye – her rigging also smoking dangerously. U-81 was better off, but was clearly out of torpedoes and held a few minor cuts and bruises of her own. U-556, to Bismarck's private relief, was the least injured of the three despite her near-suicidal charge.

The three submarines looked up to her for orders, and with only slight reluctance, Bismarck spoke.

''Full speed east. We're returning to port.''

X-x-X

Even with the three submarines aiding Bismarck, it was a hard road home – the Royal Navy was determined to not let Bismarck escape their clutches, not when she was so painfully weakened.

However they were low on fuel and ammo as it was, and their battle with Bismarck had run them nearly dry. The longer they stayed the higher the risk of Ironblood reinforcements was; a fear only aided by the presence of the three submarines. In the end, even King George V was forced to give up the chase – though not before firing one last spiteful shell in their direction, missing by a wide berth but the message remaining clear.

Upon returning to port, Bismarck was whisked away by the medics and engineers to be treated for her injuries. The more superficial, surface-layer injuries were one thing, but the damage to her Wisdom Cube and her rigging?

That was far trickier.

''They won't be able to fix it?''

It was late evening, the sky a hazy purple fading to black. Golden lights shone overhead as U-556 walked through the hallowed halls of the _Eisenkreuz_, a tall building vaguely in the shape of a cross that sat in the heart of the Ironblood port. It acted as the main home for all Ship-Girls on base, with those of higher status residing higher in the building – and, unsurprisingly, Bismarck resided at the highest point.

It was a small mercy that an elevator had been installed, otherwise Bismarck would struggle to reach the top in her current state.

''No.'' Bismarck replied, her usual purposeful stride having lost some of its grace – unsurprising, given the day she had. ''They mentioned contacting the Sakura Empire, to acquire the services of their Repair Ship, Akashi. Until then, I will have to let my wounds heal naturally.''

U-556 frowned, the idea of waiting not sitting well with her. Her worried eyes roamed over Bismarck's frame, taking note of her right arm now held in a sling. It had been saved, but only barely. However even as she walked the Battleship unknowingly leaned more on her right leg, unconsciously compensating for the lack of turrets on that side. She may be physically strong, but her turrets weren't made of paper. It didn't help that her legs were in a bad shape as well; her remaining strength barely keeping her standing.

''While your concern is appreciated, staring at me will not heal them faster.'' Bismarck stated lightly, a faint, almost undetectable note of humour entering her voice.

''A-Ah, sorry...'' The submarine smiled sheepishly, looking away with a pink blush.

''Hm. That aside... shouldn't you be returning to your room? I imagine you're quite weary.''

U-556 shook her head quickly. ''N-No, I'm fine! I- erm, I can keep going for a little longer, so Lord Bismarck gets to her room safely!''

''I was unaware there was any dangers lurking within these hallowed halls.''

The humour was impossible to miss that time. The fact Bismarck said it completely straight-faced only made it more endearing.

''T-There might be...'' U-556 muttered embarrassedly.

Bismarck hummed in acknowledgement. Any further conversation dimmed as they neared her bedroom doors, the only room on this floor – a pair of grand double doors that led to the room within. U-556 had never seen what laid behind the thick doors, but she had imagined it many times. However she restrained her curiosity – perhaps she could ask for a tour another time, when Bismarck wasn't two steps away from death.

''And at last we arrive. Without running into any Royal Navy ships hiding under the carpets.''

U-556 smiled, her heart fluttering at how... friendly, Bismarck was being. Not overly friendly like someone such as Z1 or Karlsruhe – but friendly in her own way. Subdued and dignified, but genuine. Her dry humour was much like Prinz Eugen's, but whereas the playful Heavy Cruiser was more mocking, Bismarck had a more cynical, deadpan way of joking.

''Mm. I'll, um... I'll let you get some rest then.'' U-556 said sheepishly, smiling up at the taller Battleship.

Bismarck hummed, turning to face her – before leaning down.

It was like the world suddenly slowed. Bismarck's long blonde hair fell around them, blocking out the world and dimming the golden light around them. Her face was so close, expression stoic but blue eyes shining with a surprising array of emotions, more than U-556 had ever seen before. They were so close she could feel Bismarck's breath against her face, something that made her heart skip a beat.

''Lor-?''

U-556's hesitant question was silenced as Bismarck pressed her lips against hers. For a long moment the submarine couldn't blink, couldn't breathe, couldn't think. A thousand, immeasurably fast thoughts raced through her mind – and by the time she could begin to process what was happening, Bismarck slowly pulled back.

The Battleship met her stunned gaze – a small, infinitely beautiful smile curling at her lips. ''My sincerest thanks for your unwavering loyalty, and your admirable courage, U-556. If it wasn't for you, I fear I may have been resting with Neptune at the bottom of the sea... for that, I owe you my life.''

Bismarck straightened up, still smiling slightly at the dazed submarine. ''I suggest getting some rest. Busy days are upon us. Goodnight, U-556.''

''N... Night...'' The submarine mumbled in response, watching as Bismarck disappeared into her room and closed the doors behind her, leaving U-556 standing alone in the hallway.

After a long minute she turned around, and walked back towards the elevator.

X-x-X

''Hn... U-556 is taking her time...''

''She's probably keeping Lord Bismarck company...''

U-557 and U-81 shared dull looks at that, imagining their excitable sister waiting by Bismarck's side, almost like a puppy ready for a walk. The mental image drew a slight chuckle from both of them.

Just then the door to their shared room opened, and in walked U-556 herself – an oddly dazed expression on her face, pink eyes unfocused and staring at nothing. The two submarine sisters watched in puzzlement as their normally-hyperactive sister wandered over to her bed, and mutely flopped down on it.

''…what's up with you?'' U-81 squinted at her.

U-556 leaned up, staring at her – before her lips twitched into a smile, dazed yet blindingly happy.

''Lord Bismarck gave me a kiss...''

…

''HÄH?!''

But U-556 didn't pay further attention, instead rolling onto her stomach and burying her face in her pillows, grinning stupidly and giggling happily to herself.

[END]


	2. Chapter 2: Recovery

**Oathsworn, Chapter 2**

''Hm~ hm~ hm~''

It was late morning, the dull thrumming of the elevator filling U-556's ears as it ascended. In her hands she carried a tray of food – just a simple breakfast of a couple white bread rolls, some rye bread, a few slices of cheese and a fried egg. Prepared by the cooks on the bottom floor to perfection, their performance only heightened by the fact they were cooking for Bismarck specifically.

It had been a busy morning, with U-81 and U-557 having to go to the medical bay to get their lingering wounds patched up a bit more. While they weren't very severe, it would still take a few days for them to heal naturally. The damage their riggings sustained would probably require a few more days, totalling to just under a week. In other words, the three of them got an unofficial week off work.

However with the lack of work she had plenty of free time... time she spent recalling the night prior, remembering the sensation of Bismarck kissing her, the way time itself seemed to slow, the gentle warmth and heart-melting smile she wore. It made her giddy just thinking about it, yet also left her nervous, and doubtful. Was it just a thank-you kiss? A way of appreciation?

She didn't know, and she certainly didn't want to embarrass herself – or Bismarck – by deluding herself and doing something stupid.

The elevator dinged, stirring U-556 from her musings. She hesitantly stepped out into the long hallway, idly taking in the details she missed yesterday – examining the few paintings that hung on the crimson walls, the lower half being a softer brown panelling. The occasional table was placed against the long walls, holding either a vase of flowers or small ornaments.

Soon she found herself standing before the chocolate-brown doors that led to Bismarck's room, the only room on this floor. For a moment she stood there, mentally drumming up what to say when she saw the Battleship, before swallowing her nerves – and knocking.

''L... Lord Bismarck?'' U-556 called out, raising her voice enough to be heard through the doors. ''I've, erm... I've brought you breakfast...?''

Silence. After a long moment she knocked again, but still received no response. A small spark of panic fluttered through her, concerned that Bismarck might've hurt herself in the night or maybe suffered some kind of injury in her sleep. Heart attacks on Ship-Girls were unheard of, but after what happened... one couldn't rule it out.

''I'm... I'm coming in...'' U-556 forewarned nervously, earning no reply.

After a moment more she grasped the delicately-crafted handle, one shaped like a sabre's hilt, and pushed it open. The door was a little heavier than she expected, but was thankfully unlocked – and as she opened the door she was greeted by the sight of Bismarck's personal quarters.

It wasn't as overly extravagant as she had expected, but it was certainly refined. Smooth mocha panelling lined the walls, transitioning into midnight-black wallpaper with the occasional streak of red travelling upwards. Various cabinets big and small lined the walls, one holding documents while another held liquors. A black piano sat over by the far corner while a small cluster of ornate chairs sat near the centre of the room, a small table in the middle. To her right, over by a large paned window, was a desk and large office chair. A small counter-top with various small appliances laid at the far wall near another, single door.

And over to the right, by the far wall, was Bismarck – slumbering in a king-sized bed bearing the Ironblood's flag on the covers.

''Ah, she must've been tired...'' U-556 murmured to herself, glancing back down the hallway uncertainly. It felt rude to wake her after the day she had, but it was already past ten and she _should_ get up and at least eat something.

Quietly the submarine wandered over to Bismarck's bedside, her eyes locked onto Bismarck's sleeping face – silently enamoured by the sight. She looked so... so delicate, like this. Her expression unguarded, her muscles relaxed; it was reminiscent of the expression she showed last night, right after they kissed.

_'Maybe it's her happy face...?' _U-556 pondered, blushing lightly at the thought. Or maybe it was because of how _cute _Bismarck looked – a term she never would've thought applied to the normally-composed Battleship.

She quickly shook off such thoughts, carefully laying the tray down on the bedside table and swallowing her nerves, before laying her hand on Bismarck's exposed shoulder and lightly shaking her.

''L... Lord Bismarck.'' U-556 called softly, feeling so out of place. ''P... Please wake up...''

''Nn...'' The regal Battleship grunted quietly, shifting about – until her eyes fluttered open. ''Mn... U-556...?''

''Good morning.'' The submarine greeted softly.

The blonde woman groggily raised a hand, wiping some sleep from her eye as she slowly sat up, clad in a white button-up shirt. ''What time is it...?''

''Fifteen minutes past ten.'' U-556 replied, hesitantly gesturing at the bedside table. ''I brought some food, in case you were hungry, eheh...''

Bismarck stared at her for a long moment, before smiling faintly. ''...Mm. My thanks.''

The submarine blushed and looked away, hiding her embarrassed smile. The gentle clinking of china echoed as Bismarck lifted the tray onto her lap, the soft crunch of the rye bread reaching U-556's ears – her stomach pointedly reminding her that she herself hadn't gotten any breakfast yet.

The sound of her stomach rumbling drew Bismarck's attention. ''You haven't eaten yet?''

''A-Ah, I woke up a little late.'' U-556 laughed embarrassedly, waving off the Battleship's concern. ''Nothing I can't... handle...?''

Her words died off, focusing on the white bread roll held out to her. Bismarck stared at her with a hint of amusement dancing in her blue eyes. ''Eat. It should at least keep you going.''

The expectant look on Bismarck's face quelled any arguments. ''T-Thanks...''

…

The bread roll was sweet and fluffy, the barest hint of cinnamon held within its crust. In no small part due to that she devoured it within the minute.

At Bismarck's behest she pulled over a chair, getting herself comfortable and quietly taking in the sight of the Battleship's elegant bedroom – much more lavish and organised than her own, which tended to more messy. Something that irritated U-81 to no end, given it was largely U-556 and U-557 that made the messes, and both were too lazy to clean it up.

Despite the silence she couldn't find the words to break it, her mind constantly drifting back to last night, to the kiss. The need to know almost made her squirm in her seat, eager to know yet afraid of the answer. Bismarck hadn't been in the best state, and even Ship-Girls weren't immune to blood loss – it could be entirely possible that she had been delirious, or at least mentally disoriented.

Mercifully she didn't have to break the quiet, as Bismarck did it for her. ''How are you and your sisters?''

''Ah?'' U-556 jumped lightly, fumbling for a second. ''Um, I'm fine – as you can see. U-81 and U-557 are just getting patched up. We should be ready for missions again in a week.''

Bismarck hummed. ''I'm glad.''

''What about you?'' U-556 asked curiously, her gaze wandering over to Bismarck's right arm – still held in a sling, though that did little to inhibit her movements. If anything the Battleship seemed to consider it little more than a nuisance.

''A bit of stiffness.'' She replied, rolling her left shoulder. ''My right arm is still non-functional, and will likely remain as such for several days.''

The submarine nodded in acknowledgement, privately admiring her Lord's tenacity. To ignore a damaged limb so easily, even as a Ship-Girl, was no small feat.

Cutlery clattered against china plates as Bismarck laid her utensils down, carefully lifting the breakfast tray off her lap and placing it back on her bedside table. It might've just been U-556's imagination, but the woman looked like she had gotten a bit of colour back. Considering she likely hadn't eaten in nearly a day, it wasn't overly surprising.

Bismarck sat up straighter, carefully swinging her legs over the edge of the bed. As the bed cover peeled away U-556 became distinctly aware of how little clothes Bismarck was wearing underneath – specifically, only a pair of black panties to go with her button-up shirt. The sight of her Lord in such little clothing...

''I may require assistance in getting to the bathroom, given my weakened state.'' Bismarck stated lightly, unaware of U-556's flustered thoughts. ''Would you mind...?''

''Ah? Y-Yeah...'' U-556 blushed, rising to her feet and taking Bismarck's hand – pointedly trying to avoid looking at Bismarck's long, creamy legs...

_'Bad thoughts~!'_

X-x-X

A few hours passed, and U-556 managed to survive without passing out from either nervousness or embarrassment.

Now, as the clock ticked over to two o'clock, the submarine found herself carrying another food tray – this one holding two separate lunches, one for each of them at Bismarck's behest. The notion of eating lunch beside her beloved Lord was enough to make butterflies tickle her stomach, but she kept her composure. Barely.

The elevator dinged and the doors slid open, revealing the long hallway leading to Bismarck's grand room. U-556 quickly made her way towards her Lord's room, glancing down at her lunch and licking her lips eagerly.

''_Schei- gah!_''

Her attention immediately focused on the sudden shout, heart sinking as she recognised Bismarck's clearly-pained voice. ''Lord Bismarck!''

It was only a short few second dash to the doors, hastily shoving the door open with her shoulder. Her eyes instinctively scanned the room for threats but found none – instead, she found Bismarck laying on her front before her bed, face twisted in pain as she struggled to rise back up on her weakened legs.

She quickly laid the tray down on a nearby table and rushed over to her superior, worry coldly burning in her chest. With a grunt of effort she grasped Bismarck's one good arm, helping the taller woman up and onto her bed. She was uninjured, thankfully, but from the looks of things she had fallen on her bad arm, which had to hurt.

''A-Are you alright?'' U-556 asked worriedly.

The Battleship didn't meet her gaze, harshly yanking her arm free from the submarine's grip, pride visibly wounded. U-556 flinched, instinctively pulling back as if afraid of retaliation for her actions.

Bismarck paused, glancing at U-556 and meeting her hurt gaze. For a long moment neither moved, before Bismarck lowered her hand and screwed her eyes shut, sighing deeply.

''I... I'm sorry.'' She apologised softly. ''I am not used to being so... so weak, so helpless. You are not at fault, and it was wrong of me to direct my anger at you.''

''I-It's fine...'' U-556 smiled hesitantly, reassured Bismarck wasn't mad at her. ''It's normal to feel like that, especially someone as strong as you, Lord Bismarck... but, please remember to take it easy. That way you can get stronger faster.''

A spark of confidence fluttered through U-556 and she grasped onto it, boldly stepping in front of Bismarck – taking her hand and drawing her full attention.

''Besides... you don't _need _to be strong, right now.'' U-556 told her with a warm smile. ''Because you have the entire Ironblood fleet behind you. And I'll stay by your side as long as you need me!''

Bismarck blushed prettily and looking away – doing little to hide her small smile. ''_Danke..._''

X-x-X

Many more hours passed, the day bleeding away as U-556 found herself acting almost like a maid for Bismarck – a duty she gladly did with a smile on her face.

The skies outside darkened swiftly as night descended, the clock ringing as it passed eight o'clock. At Bismarck's request she had turned off the overhead lights, instead leaving the room only illuminated by the lamps that hung from the walls or sat atop tables, giving the room a much softer glow to it. Light shadows danced across the floor and crept up the walls like playful spirits, flickering at the slightest movement from the room's occupants.

U-556 found herself sat in one of the ornate but comfy chairs, a small table before her with a chess board atop it – and across from her sat Bismarck, a thoughtful expression on her face as she planned her next move. While chess wasn't U-556's cup of tea, it was an oddly pleasant change of pace – though sitting across from her Lord certainly helped ease her usual excitability.

However despite the game in front of her she found her mind wandering. Once more about the kiss. It had been a small itch at the back of her mind the entire day, briefly forgotten during the afternoon only to come back stronger during dinner. Being so close to Bismarck yet unaware of where they stood with one another, it made her want to roll on the floor in frustration. Yet she couldn't muster the courage to simply _ask_.

Her eyes discreetly flickered up to Bismarck's beautiful face, her heart fluttering at the mere sight. The more she thought about it the more uncertain she became, not only of their relationship, but also of her own feelings. What _was _Bismarck to her? A Lord? A friend? A _lover_? She struggled to define the feelings burning within her, only adding to her frustration. On one hand she wanted nothing more than to hug and snuggle with Bismarck, yet at the same time she was aghast she would even think of doing such a thing with her 'Lord'.

''Checkmate.''

U-556 was snapped from her complicated thoughts at the sound of Bismarck's voice, blinking and turning her gaze onto the chessboard – finding her King surrounded. ''Aw~! And I was so close too!''

Bismarck smiled slightly, amusement glittering in her blue eyes. ''Perhaps next time you will triumph.''

The submarine pouted in reply, eliciting a quiet chuckle from the Battleship. The sound easily made her pout dissolve, transforming into a light grin – so fast she didn't even consciously realise she was grinning until a second later.

As she leaned back in her chair the shadows around the floor danced lightly, the light behind her casting a shadow over the far wall and reflecting off something. ''Huh? What's that door over there for?''

Bismarck looked over her shoulder, taking notice of the small wooden door in the corner of the room. ''Ah. That leads outside – would you like to see?''

With nothing else to do, U-556 nodded. ''Mm!''

The submarine hopped to her feet, moving over to Bismarck's side and offering her hand – helping Bismarck to her feet and holding onto her, letting the Battleship use her for support. Even though she had done this manoeuvre several times already, her cheeks still dusted pink with embarrassment.

Upon reaching the door Bismarck snagged a key off a nearby hook, unlocking the wooden door and turning the brass knob. The door swung outwards, revealing a modest balcony – and as U-556 stepped outside she was granted the view of the entire port, countless golden lights glittering below from the many windows.

''W... Wow...'' U-556 murmured, walking over to the edge and leaning on the stone railing, small little pillars connecting it to the balcony.

''Indeed; an impressive view.'' Bismarck agreed lightly, putting her weight on the railing. ''I come out here often on evenings. You can see the sun rise and fall from here, and see the whole base awaken and slumber.''

The blue-haired submarine nodded slowly, not doubting that for a second. Looking at the buildings from below made them seem so imposing, so tall – but looking at them from above, with even the High Command buildings being dwarfed by several stories... it felt like she was a plane, high above the clouds.

There was no lights on the balcony, leaving only the soft golden glow of Bismarck's room to illuminate the stone balcony. U-556 glanced to her side, absorbing the sight of Bismarck's fond expression – a faint smile curling at her lips, gaze soft and warm.

Dimly she realised that due to how late it was, she would have to return to her room soon so Bismarck could sleep. And she wasn't sure if she could sleep with this burning feeling in her heart.

''U-Um... Lord B-Bismarck?'' U-556 hesitantly spoke up, drawing the Battleship's attention.

''Yes?''

''I-I was wondering... about yesterday.'' She fidgeted nervously, summoning her courage and meeting Bismarck's curious eyes. ''About the kiss.''

The blonde blushed faintly, looking away. ''...ah. I see.''

Her tone was neutral, almost embarrassed, so U-556 continued on. ''W-Was it just a... a thank-you kiss? Or... um, was it... y'know... _more_ than that?''

Bismarck was quiet for a second, before slowly nodding. ''It was... a gesture of affection. I find myself ensnared by your charms, U-556. Your unfaltering loyalty, your devotion, your adoration. It is impossible to deny the warmth that blossoms in my heart when I merely think of you.''

She turned towards U-556, smiling warmly – gently cupping the enamoured submarine's chin. ''I dare say, that this feeling is what many call... _'love'_...''

Bismarck leaned down, and unlike the first time U-556 was ready – happily returning the gentle kiss, nearly giggling from the sudden lightness in her chest. The kiss lasted only a few seconds yet it felt so much longer, the softness of Bismarck's lips becoming engrained in her mind forever.

''It's getting quite late...'' The Battleship remarked softly as she pulled back, her smile not leaving. ''It would be inappropriate to send you back alone at such a time as this, lest any Royal Navy ships emerge from the hallway carpet. So if it is no trouble, would you mind... spending the night with me?''

U-556's bright smile and charming laughter was all the answer Bismarck needed.

[END]


	3. Chapter 3: Reunion

**Oathsworn, Chapter 3**

''Mnaah~''

U-556's drowsy yawn fluttered through the bedroom as the blue-haired submarine awoke. After a second of staring at the ceiling she groggily rolled onto her side and sat up, wiping some sleep from her eyes. The morning sun peered through the windows and illuminated the room, the distant caws of seagulls reaching her ears.

Gentle movement behind her made the submarine turn slightly, a warm smile fluttering across her face as her eyes laid upon Bismarck's sleeping form. Her blonde hair splayed about the pillow and a thin strand hung from the corner of her mouth, her regal face scrunching up from U-556's movements. For someone so dignified, so professional... she looked adorable when she slept.

''Wakey-wakey, Lord Bismarck~''

''Nn...'' Bismarck grunted softly as U-556 shook her, reluctantly opening her eyes. ''I'm awake...''

U-556 giggled happily in response, stretching her arms above her head.

It had been several days since the Battle of Western Brest, as it was now dubbed. Since Bismarck had confirmed their mutual feelings, U-556 had spent nearly every day by Bismarck's side – only ever leaving to get food, report to her superiors or to grab something from her room. She slept with Bismarck in her bed, washed in her bathroom and ate in her room, assisting the Battleship with anything she desired.

Safe to say, U-556 had been over the moon for days now, something U-557 dully noted whenever they ran into each other.

Bismarck grunted softly as she sat up, planting her arms behind her for support. Her right arm was now healed enough to be removed from its sling, but her rigging was still a long way away from being fully operational. Damaged turrets was one thing, but completely destroyed turrets? That wasn't so easily repaired. Only a Repair Ship could feasibly do it, and even then it'd take a full day minimum. And unfortunately the Sakura Empire held the _only _Repair Ship between the two nations; it was an understatement to say she was a busy girl.

The blonde Battleship swung her legs over the side of the bed, rubbing her eyes groggily. Without a word U-556 slipped out of bed and wandered over to Bismarck's side, taking the woman's hand and helping her to her feet. The gesture came naturally and without hesitation to U-556, in no small part due to how often she did it.

''How's your legs, Lord Bismarck?'' U-556 asked conversationally, helping the Battleship over to the nearby counter-top.

''Better. I should be able to walk normally under my own power within the next day or two.'' Bismarck responded lightly, before gently poking U-556 on her forehead. ''I also recall telling you to drop the 'Lord' title. At least in private.''

''Ah... my bad, eheh...'' The submarine giggled sheepishly. Once upon a time she asked for the honour of calling Bismarck her 'Lord', but in this situation she could hardly mourn the loss.

Not when she could to be so close to Bismarck, physically and otherwise. Turns out Bismarck made a good hug-pillow for sleeping.

The coffee machine bubbled as it brewed a fresh batch, hissing as Bismarck poured it into two separate mugs – adding several plentiful teaspoons of sugar to U-556's. The older woman quietly nursed her mug and leaned against the counter, smiling fondly as the blue-haired submarine swung her drink back.

''Mm~'' U-556 hummed happily, sighing in content as she pulled the mug away. ''You wanna go in the bath first?''

''No. You may go first.'' Bismarck replied, pausing as she took a sip of her coffee. ''You will have a few minor duties to attend to, whereas I will only have to sit and sign documents. They can wait, your duties may not.''

U-556 pouted, countering with her own suggestion. ''But what if you hurt yourself while I'm gone? Bathtubs can be pretty slippery, y'know?''

The blonde Battleship sighed quietly, relenting. They had a similar debate the morning prior, and Bismarck had learnt how stubborn U-556 could be, especially when it came to her safety. ''Very well.''

…

The muted sound of rushing water was pleasant to listen to, mixing with the distant noises of the base waking up in full.

U-556 stood before Bismarck's closet, humming to herself as she collected a fresh uniform for herself. Bismarck had been kind enough to lend her a drawer to put her things in, given she was sleeping and waking here – it didn't hurt that her 'uniform' was essentially just a swimsuit and jacket, while her sleepwear was merely a shirt and underwear.

As she hung her uniform over her arm, a polite but insistent knock at the door drew her attention. U-556 briefly glanced at the bathroom before curiously approaching the main doors – it wasn't often Bismarck got visitors, much less at this time. Usually it was only Prinz Eugen who dropped by late afternoon for 'a chat', but was in actuality more of an excuse to avoid menial work.

Gripping the sabre-styled handle, U-556 tugged the door open – and revealed U-81, in full uniform.

''Good morning, sister.''

''U-81?'' The blue-haired blinked. ''Er... hi? What's up?''

''Letter from High Command.'' U-81 drawled with a vague sense of annoyance, clearly displeased with being what amounted to a mail-woman. ''Also, you probably shouldn't answer the door in your underwear, _while _in the room of _Bismarck_ herself. Not a good look.''

U-556 glanced down, blushing lightly as she realised that fact. Had it been a regular officer or even another Ship-Girl... yeah, that'd be pretty embarrassing. And possibly started some unwarranted rumours.

''Right. I'll, um... I'll remember that.'' U-556 smiled sheepishly, earning an amused huff from her pink-haired sister.

''See that you do. I'll see you down at the docks.''

''Eh? W-Wait, why am I-'' U-556 half-started, but U-81 was already walking down the hall.

''Read the letter!'' The submarine shouted over her shoulder.

U-556 stuck her tongue out and blew a raspberry at her fleeing sister, earning a flat look from U-81 before the elevator doors closed, taking her back down the building.

''Hmph. Read the letter, she says...'' U-556 pouted petulantly to herself, digging her nail into the corner of the envelope and ripping the top open. ''She could've just told me...''

Her attention was quickly grabbed by the contents of the letter, idly closing the door behind herself. She had to re-read several paragraphs over, making sure to soak in each word lest she have misread them. However by the end of the letter, signed by some bigwig she didn't care about, she was nearly grinning with excitement.

Just then the door to the adjoined bathroom opened, Bismarck exiting clad in full uniform. Her long blonde hair was still slightly damp but otherwise neatly brushed, her cap resting on a nearby table.

''You seem to be excited.'' Bismarck noted curiously.

''Mm! Look!'' U-556 eagerly held out the letter to Bismarck, who carefully took and read it.

_Dear U-556, Squadron Leader of Unterseeboot Group K,_

_You are hereby tasked with the duty of escorting Battleship Tirpitz from the Northern Seas to your current assigned post near Brest, following the recent assault on Flagship Bismarck._

_You will be accompanied by your sister-ship, U-81, and Destroyers Z20, Z21 and Z25. Battleships Scharnhorst and Gneisenau will be en-route back to your assigned post, and will be in range to assist should your convoy come under fire._

_Additionally, Aircraft Carrier Graf Zeppelin will be on standby to launch supporting aircraft should the need arise._

_You are to report to your base commander by 9:00AM. Assuming good weather conditions, you are expected to meet up with the convoy by noon._

_Long live the Fatherland._

_Regards,_

_Admiral Kriegsmarine_

''_Schwester..._'' Bismarck muttered softly, lowering the letter. ''So the time has come, for us to meet at last...''

''Yep~!'' U-556 grinned broadly, giving a cheerful salute. ''Don't worry, I'll bring her back swiftly!''

''I trust that you will.'' The blonde Battleship smiled slightly, before it disappeared. ''Though I'm worried about High Command sending you out, so soon after returning. Did you not say that you would have the week off?''

''Eh, maybe the doctors told them we were fit enough?'' U-556 shrugged. ''Doesn't really bother me; I'm pretty much back to normal anyway. U-81 looked fine enough when she delivered the letter too – U-557 was the worst injured of us, so that's probably why she isn't coming with us.''

''True.'' Bismarck accepted, laying one hand on her knee and bending down.

U-556 blushed but gladly met Bismarck halfway, returning the gentle kiss. Like always it never lasted for long, yet it still left her heart fluttering warmly. After a long moment Bismarck pulled back, kindly raising a hand and cupping U-556's cheek, running a thumb along her peachy skin.

''A good-luck kiss, as it were.'' Bismarck said softly, smiling lightly. ''I will await your return with open arms, my Knight.''

''Eheheh...'' U-556 giggled, grinning bashfully. ''I-I'll do my best!''

The Battleship chuckled, rising back to her full height. ''I know you will. You may wish to shower and change before you leave, however.''

''A-Ah, right!''

X-x-X

''Convoy ahead. Closing in one minute.''

U-556 hummed in reply, acknowledging U-81's report. The open ocean stretched out in every direction, the surface of the water a sparkly blue that seemed to shine under the sun's hot rays. It reminded her of that one time she went to a beach, a few months before the war started. Maybe she could convince Bismarck to come with her – she wasn't sure what kind of swimwear the Battleship would wear, but... well, her mind helpfully provided many images.

''Oi. Head out the clouds.'' U-81 droned tonelessly, snapping U-556 from her fantasies.

''R-Right.'' U-556 shook her head quickly, revving her rudders and picking up speed.

Up ahead was the convoy, consisting of a white transport boat with the three Destroyers – Z20, Z21 and Z25 – sailing around it in a triangle formation. And stood upon the right side of the boat, was Tirpitz. The woman looked remarkably like her sister-ship, yet at the same time looked nothing like her. Their hair seemed so different not just in colour but in fashion, their facial structure was subtly different, even their figures seemed to be distinct. The only thing connecting them was their shared clothing design.

It was Tirpitz's eyes that convinced U-556, however. A chilling steel look to them, tempered by years of war. But where Bismarck was hardened by the burden of leadership, Tirpitz was hardened by something else – something U-556 couldn't begin to fathom.

Dispelling such heavy thoughts, U-556 sailed up towards the boat – nodding in greeting to Z25 as she passed, swerving around to she could sail up alongside the small transport ship. After making sure her rigging was steady U-556 rose to her feet, carefully balancing herself on her moving rigging before bending her knees – and kicking off her rigging, leaping into the air.

''Alley-oop~!'' U-556 declared mid-flight, flipping through the air before landing feet-first on the main deck. ''Tadah~! Parzival of the Seas, U-556, has arrived!''

Tirpitz stood mere feet away... looking rather unimpressed.

''While I applaud your trick, doing such a thing out in the open ocean is unwise.'' The cool-eyed Battleship stated, her voice sharp but not entirely unkind. ''I would advise you in future to not behave so foolishly.''

U-556 pouted. ''It's only a little jump. I've done way bigger stunts before, y'know~?''

''That only makes me more troubled, rather than less.''

''Would you feel better if I showed you my bigger stunts~?''

''No, I would not.''

_'...much less friendly than Bismarck.'_ U-556 thought dryly.

Before any further conversation could continue U-81 also boarded the boat, dismissing her rigging. ''You should be more respectful, U-556. Just because she's Bismarck's sister doesn't give you the right to act so friendly, you know.''

''I know, I know, I just wanted to give a good first impression is all...''

''Since when has your stunts ever gotten you a good impression?''

''Well, Karlsruhe liked my backflip...''

Tirpitz's attention focused acutely on the submarine. ''You speak as though you know my sister closely.''

U-556 blushed and giggled nervously, scratching the back of her head. ''Erm... y-yeah, we're um... we're close.''

Beside her U-81 snorted. ''_Close _is putting it one way.''

Tirpitz raised a brow curiously, wondering exactly _how _close the two girls were implying – but before she could voice her curiosity, Z20 spoke up. ''Hey, U-556! Your rigging is sailing away without you!''

''H-Huh? Ah, crap!'' U-556 rushed over to the side of the boat, spotting her submarine-shaped rigging slowly veering away from the convoy. ''H-Hey, Z20! Gimme a lift!''

''Hehe, roger~! Breaking away from the convoy~!''

''F-Faster! It's getting away!''

''I can't with how much you're struggling-! Hey, how about I throw you instead?''

''Good idea! Parzival... _torpedooo~!_''

As Tirpitz stood and watched U-556 fly through the air towards her rigging, she discreetly leaned down to the dull-faced U-81.

''Forgive my bluntness, but does this... happen often?''

U-81 only pinched the bridge of her nose, and sighed. ''You have no idea.''

X-x-X

''Right this way, Miss Tirpitz~!''

It was mid-afternoon by the time the convoy returned to base, thankfully unharmed and unspotted by any enemy vessels. U-81 helped carry Tirpitz's luggage up to her room – two floors below Bismarck's – before departing, leaving U-556 to guide Tirpitz up to Bismarck. Something the submarine quite happily did, excited to see how the two sisters would get along.

''Hn.'' Tirpitz spoke up slowly. ''I do wonder if my sister and I will get along... this will mark the first time we've met.''

''Heh, I'm sure you'll get along fine~!'' U-556 cheerfully replied, the elevator dinging as the door opened, revealing the long hallway that led to Bismarck's room. ''You're actually a lot alike, y'know? She's been anxious to meet you too – she told me when she nearly sunk not long ago, she was afraid she would sink without getting to meet you!''

''...I see...'' Tirpitz murmured quietly.

U-556 giggled. She even had the same stoic, faintly-hopeful expression Bismarck occasionally held.

The duo reached the grand doors leading to Bismarck's room. With a dramatic flair U-556 heaved the doors open, watching Tirpitz's reaction out the corner of her eye. The change was subtle but still there – from the slight widening of her eyes, parting lips and flicker of awe in her eyes. Truthfully Bismarck's room may not be the grandest room on the base, but there was a certain wonder to it; like the difference between an empty throne, and Neptune's throne. The person residing on it made all the difference.

And sitting in one of the chairs was Bismarck, a faint smile gracing her expression as she rose to her feet. ''_Schwester... _allow me to personally welcome you to our port.''

Tirpitz nodded, a brief flicker of hesitation fluttering through her before she pushed it aside, entering the room. ''Mm. This day has been long overdue, hasn't it?''

''Indeed.'' Bismarck agreed wholeheartedly, shaking Tirpitz's hand. ''Please, sit. We have much to talk about.''

''That we do.'' The white-haired Battleship hummed, lowering herself into an empty seat. ''I heard from High Command that you were severely injured, not long ago. I hope you won't be out of commission entirely, not with the Royal Navy looming beyond the horizon.''

''You need not fear.'' Bismarck assured, briefly glancing behind her – to where U-556 was making some fresh coffee. ''While my injuries were heavy, I have mostly recovered physically. My turrets remain damaged but are expected to be repaired by the Sakura Empire Repair Ship, Akashi, according to a messenger. Within a week I should be back to my full strength.''

''I see... that's good to hear.''

Their light conversation stilled for a moment as U-556 walked over, laying down a little wooden tray with two mugs of coffee and some biscuits. Bismarck smiled warmly and affectionately petted the submarine, running her fingers through U-556's blue hair and eliciting a happy giggle from the younger girl.

''My thanks.'' Bismarck said gently, looking over at Tirpitz. ''I was saved from sinking thanks to U-556 here. Had it not been for my faithful _'Knight_', I would almost certainly have been resting at the bottom of the sea.''

Tirpitz smiled softly. ''I'm glad. It puts me at ease to know you have such a 'faithful Knight' by your side.''

Privately however, Tirpitz truly began to understand what U-556 meant earlier when she said they were 'close'.

_'Seems like I need not be concerned about your safety, dear sister...'_

X-x-X

Hours passed in a what felt like minutes, the two sister-ships growing more comfortable with one another and chatting away ceaselessly. By the time they realised it, night had fallen. Tirpitz then departed back to her room after promising to visit tomorrow afternoon, letting U-556 and Bismarck head off to bed.

''See, I told you that you'd get along.'' U-556 remarked lightly, sitting on the edge of the bed and swinging her legs, watching as Bismarck walked around the room turning the lights off.

''Mm.'' The Battleship hummed in response, her regal face illuminated by the wall-mounted lamp – revealing her small, warm smile. ''She is everything I expected of her.''

U-556 smiled slightly at Bismarck's response, knowing how much meeting Tirpitz truly meant to the Battleship. Bonds between sister-ships were precious, and to have never even met Tirpitz must've ate away at her for many months. While it might mean she would have less alone time with her newfound 'partner', she didn't mind.

As the last of the lamps went out the room was plunged into near-complete darkness, only a single bedside lamp glowing by U-556's side. Writhing shadows danced along the walls as Bismarck approached the bed, dressed in her usual choice of sleepwear; a partially-unbuttoned white shirt and a pair of black panties. The sight always made U-556 blush lightly, but kept her embarrassing thoughts to herself.

''Light.'' Bismarck said simply, peeling back the covers and slipping under them.

''Mm.'' U-556 hummed in reply, flicking the light off and plunging the room into total darkness.

The submarine wriggled under the covers, greedily pulling them up to her shoulder and shifting over towards Bismarck. The older woman sighed with quiet exasperation, a fond smile gracing her beautiful face as U-556 snuggled against her like she was an oversized hot water bottle. That thought was only reinforced as U-556 settled her head against Bismarck's shoulder, their legs intertwining beneath the covers.

Bismarck breathed softly, placing a gentle kiss on U-556 forehead. ''Goodnight, my Knight.''

''Night~''

And like the nights before, Bismarck let herself drift off into a pleasantly dreamless slumber.

[END]


	4. Chapter 4: Celebration

**Oathsworn, Chapter 4**

Nearly two weeks had passed since the Battle of Western Brest.

In that time not a lot had happened – the Royal Navy had kept their distance and the High Command had ordered all Ironblood ships to remain at their ports, presumably in case of an attack. Bismarck wasn't bothered by this, as it meant she had more time to spend with U-556 and Tirpitz, and even getting several visits from a bored Prinz Eugen. Life had almost seemed _'normal'_, a decidedly pleasant feeling compared to the usual drums of war.

Akashi had also been escorted to the port by a small fleet of Sakura ships and successfully healed Bismarck to full capacity, but even then High Command reinforced the previous order – all ships to remain at base.

Now, Bismarck understood why.

''Can you repeat that?''

The human officer before her was on the older side and equally high-ranked, but even still he shrunk away from her sharp gaze. ''O-Of course. A-As of this day, the Ironblood and Sakura Empire have entered a ceasefire with the Royal Navy and Eagle Union, in light of the growing threat of the Sirens. The_ Four Great Powers _came to this decision unanimously, so it is not a surrender, and no nation will suffer consequences for actions done throughout the war, barring war crimes, in exchange for refocusing all forces on the Siren threat.''

It took Bismarck a few seconds to truly soak in his words, unable to fully hide her surprise as she dismissed him. Watching the officer walk away Bismarck slowly closed the door, a bizarre numbness flooding her as she stumbled over to a nearby chair and promptly collapsed in it, dazed.

That was the sight U-556 was treated to as she exited the bathroom, her cheeriness instantly giving way to concern. ''B-Bismarck? Are you alright? You didn't have a fall again did yo-''

''The war is over, my dear Knight.''

U-556 froze, staring in stunned disbelief at her idol – the blonde woman tilting her cap down to hide her eyes. Silence reigned heavily on the room, as if gravity itself suddenly doubled only for them. With her hat hiding her eyes it was impossible to tell what Bismarck was thinking, but the way her jaw tensed dangerously and threatened to reveal her gritted teeth... it was clear of how she felt.

''H-How...? Did we lose... _again?_''

''No.'' Bismarck quickly crushed that fear. ''We... entered a ceasefire. High Command has decided the Sirens are a bigger threat. As of this moment, the Royal Navy is officially no longer our enemy.''

Slowly U-556 walked up to Bismarck's side, worriedly laying a hand on the woman's arm. ''Bismarck...?''

''Do they take us as fools...?'' Bismarck asked harshly, but U-556 knew it wasn't directed at her. ''We fought, we bled, we _sunk_ for our homeland. We razed cities and destroyed convoys. All for our ideology, for our gods, for our way of life – and they seek to throw it away, merely because the _Sirens_ are a greater threat? Do they think us incapable of fighting war on two sides? The Northern Union was stifled by Tirpitz alone. The Iris Libre was brought to their knees in a matter of weeks.''

''And yet...''

U-556 remained silent as Bismarck spoke, as she _vented_, watching as Bismarck visibly struggled for the words to express her anger, her disdain – her _sorrow_.

''All of it... was for nothing?''

With careful slowness U-556 reached out, gently grasping the front of Bismarck's cap and pulling it back, meeting the Battleship's torn gaze. Unlike Bismarck, who dealt with politics and wore the burden of leadership, U-556 had no such concerns. She didn't care who she sunk and for what reasons. She didn't care for the war. But she knew that Bismarck did, and that was enough to make her care.

''What do you need me to do?'' U-556 asked softly, but with an undertone of confident resolve. Anything asked of her she would do, if it meant easing Bismarck's pain.

Bismarck stared into her eyes for a long few seconds, as if absorbing her confidence, before she took a deep, contemplative breath. ''I... there is nothing we can do. The High Command's word is absolute, and I will not start a civil war for my own selfish desires. However there will be chaos – only a minority will accept their word without question. Many of the more experienced and patriotic will rebel against it.''

The submarine frowned, racing for an idea to salvage what would soon be a (possibly literal) powder keg – before an idea hit her. ''How about a party?''

''...what?''

U-556 smiled brightly, the idea taking root in her mind and confidence blossoming in her heart. ''A party! You know, with balloons and music, some fancy banners, a little speech from you and lots of food, and-''

''Why?'' Bismarck asked, genuinely lost and unable to see the benefit – if anything, having all the Ship-Girls loaded into a single room was practically asking for trouble, especially with the politics involved.

U-556's smile grew into a grin. ''Simple. What we did, the war... it _wasn't _for nothing! We may've not won, but we didn't lose either! We learned, we got better, we made cooler tactics, we _improved!_ We lost less ships than last time, we forged new tech, we've become one big family!''

''So how about a party... to remember who we lost, _and_ what we gained!''

Bismarck was left stunned, mouth slightly agape and not even trying to hide her surprise. It was such a silly idea, but U-556's words rang true. They _had _learned, they _had _gained something. Maybe it wasn't territory or a medal or the pride of their kin, but something more immaterial – deeper and long-lasting.

''Hm...'' Bismarck tilted her head down, shoulders shaking lightly. ''Hmhm... hmhmhm...!''

For the first time in _months_, Bismarck truly laughed – the foreign sound drawing a bright blush from U-556. It was a soft but refined sound that slipped from her lips like a warm breeze, musical in a way that sounded almost angelic to the blushing Submarine.

''Forgive me...'' Bismarck covered her mouth, stifling her soft laughter. ''Your insight still surprises me, U-556. I will bring the idea to the admiralty and push for their approval. I don't imagine it will be hard to convince them, given the situation.''

U-556 grinned cheekily. ''Do I get a 'good job' kiss~?''

The Submarine quickly yelped as Bismarck looped an arm around her, pulling her over the arm of the chair and bringing their faces close – allowing Bismarck to give her a distinctly passionate kiss, melting U-556's mind in an instant.

Breaking off from the kiss, Bismarck hugged the submarine close – and whispered in her ear. ''You may get much more than that, _my adorable Knight_.''

The sight of U-556 glowing scarlet and spluttering was more than enough to draw a smile from Bismarck, allowing herself to forget her worries, if only for a moment.

X-x-X

Two days had passed. The news of the war ending had wrecked havoc on the base's inhabitants, but the reveal of a party – officially called a 'Celebration' – had quelled most bitterness. Instead leaving many confused at the sudden announcement, and a bit curious.

It didn't help that U-556 had sent out hand-drawn invitations to half the Ship-Girls on-base, to both the amusement and bewilderment of some.

Bismarck sat behind her desk silently, frowning thoughtfully and idly tapping her pen against her paper. It was late afternoon by this point, with the party scheduled to begin in the evening. All Ship-Girls on base were invited to attend, and while it wasn't said it was implied that attendance was mandatory. She didn't like adding that stipulation, but she felt that people needed to hear what she said. Many of them looked up to her as _their _leader, rather than the High Command or the admiralty. Even if they chose not to accept her words, as long as they heard them, she would be content.

Thankfully many of the Destroyers and submarines had been easy to convince, with U-556 doing most the work – but the older and more cynical ships needed some convincing, mostly the cruisers and Battleships. Thankfully Prinz Eugen took care of that, though not without her silver tongue.

''Hey, hey! Bismarck~!''

Bismarck looked up from her work, blinking slightly as U-556 skipped out the bathroom wearing a new dress. It had a cutesy charm to it, being a strapless white dress with a thigh-length skirt and a black ribbon wrapped around her midsection. Adding to its charm was a little blue flower pinned at the top, contrasting the white-fur mantle she wore to cover her shoulders. She had even picked out cute little dress shoes and fur gloves to match.

''Look~!'' U-556 grinned brightly, doing a twirl and flourish. ''Like it?''

''It certainly suits you. You look lovely in it.'' Bismarck smiled amusedly, earning a pleased giggle from the submarine.

U-556 skipped closer, curiosity blossoming on her face as she gazed down at the paper in front of Bismarck. ''What's that?''

Bismarck's eyes flickered down. ''The speech I have planned for tonight. I'm... struggling to tell if it would be acceptable. Tensions are running high, and one slip of the tongue could anger many, and with power like ours such anger is dangerous.''

The petite Submarine had to agree with that. She couldn't imagine what kind of damage a furious Deutschland or Graf Zeppelin could do. She shivered at the thought.

''Well... how 'bout using me as a sounding board?'' U-556 offered, rocking on her heels idly.

The blonde Battleship smiled lightly. ''Very well...''

Minutes bled by, the ever-steadfast voice of Bismarck reciting the lines of her speech with flawless intonation. U-556 listened and offered a few suggestions, Bismarck corrected her work, and the process repeated. Soon minutes turned to hours, and the rest of the afternoon quickly bled away as the repeated lines of Bismarck's speech wove through the air, carried by her voice.

By the time they were finished the sun was beginning to dip near the horizon, painting the sky a pleasant amber – the clock signalling it was nearing five. Bismarck glanced at the clock, mentally calculating how long it would take to get into her dress and finish preparations on her side. It was tradition that Battleships would arrive near-last, since they were slower on the battlefield. Symbolic, if nothing else.

Setting down her papers with a satisfied quirk to her lips, Bismarck stood up. ''My thanks, U-556. I wouldn't have been able to do as much work as I have without your assistance.''

The Submarine blushed and grinned happily, puffing her chest out with pride. Bismarck smiled amusedly, reaching over the desk and gently cupping her chin, tugging her closer and allowing the taller woman to lean down and kiss her. She purposefully let it last longer than before, savouring the softness of U-556's lips, before pulling back.

''Ehehehe~'' The blue-haired girl giggled dazedly.

Shooting the love-struck U-556 an amused smile, Bismarck departed for the bathroom, intent on getting dressed first and foremost.

X-x-X

The party was in full swing, Bismarck noted idly.

It was hosted in the main lobby of the _Eisenkreuz _building, the vast space provided ample room for Ship-Girls to mingle and murmur conversations. Despite the tension in the air there was also a certain lightness, reluctance mixing with grudging acceptance. And who else was responsible but U-556 and her sisters, wandering around and 'coincidentally' chatting about all the cool things they could do now, that they weren't at war with the other Great Powers?

''Things certainly seem bright.''

Bismarck glanced to her right, eyeing Tirpitz as she approached her throne. Her sister wore a lovely white evening gown with a cape, parting around the chest area and revealing plenty of pale skin.

''Indeed.'' Bismarck hummed, gently resting her cheek on the back of her hand. ''I have to credit U-556 and her sisters for such brightness. Their innocence purifies us of our misgivings.''

Tirpitz smiled slightly. ''You speak as if from experience.''

''Perhaps. News of the war ending hit us all differently.''

''Mm. I understand that feeling deeply, _Schwester_. Believe me.''

''Believe I do.''

Their light discussion was interrupted as Prinz Eugen drifted over to them. The busty Heavy Cruiser wore a strapless black dress that fell to her thighs, the wavy fabric a dark burgundy on the inside. A translucent black fabric stretched from her collar to the bust of her dress, keeping everything attached, though it did little to hide the sides of her breasts. Not that the cruiser minded, clearly.

''Who would've thought that we'd agree to a ceasefire?'' Prinz Eugen mused lightly, having enough tact to keep her voice low.

Bismarck tilted her head in acknowledgement. ''I certainly didn't. But the High Command surely didn't take this option lightly. Irregardless of our thoughts about them, they know better than to alienate us mindlessly. This decision likely weighs as heavily on them, as it does us.''

Prinz crossed her arms, conceding to her point. ''Maybe. But I don't do politics. Do _you _think they actually care? They hardly seem to mourn us when we sink.''

The blonde Battleship shook her head slowly. ''I believe they do. Mourn in public they may not, but their hearts yearn for our return. I could see it in their eyes when they have to deliver the news of our fallen. Our people are not the kind to expression their sorrow for all to see. We are born of iron and blood, and sorrow has no place with either. I'm sure you know that intimately.''

Prinz Eugen smirked slightly. ''Ah, but what about _love_, hm? Does that have a place in our world?''

Bismarck knew a diversion when she saw one, but held her tongue. ''Indeed so. Iron we may be, but even iron can be melted by the warmth of another.''

''Such as a certain Submarine?'' Tirpitz couldn't help but pitch in, a slight smirk dancing across her lips.

''...perhaps.''

Both Tirpitz and Prinz Eugen chuckled at Bismarck's slight delay, the embarrassment clear on the blonde's face. She may not be as expressive as the average person, but that didn't mean she didn't have emotions. It merely took more prodding to get a reaction.

Glancing up Bismarck noted the time, slowly laying down her forgotten wine glass and rising to her feet. Even though many were engaged in conversations of their own, it took only a matter of seconds for all chatter to completely cease, leaving the hall in utter silence. Countless eyes turned towards her, a myriad of emotions dancing within their eyes. Respect, envy, determination, arrogance. She was their symbol and their leader. And she would fulfil that duty until the end of her days.

Tirpitz and Prinz Eugen had stepped away, still standing close but far enough away to not divert attention from Bismarck. The blonde let her eyes wander for a moment, meeting the eyes of every Ship-Girl in the room. Many shied away, some gazed back strongly, few glared, and one grinned reassuringly. She took reassurance in the last one, silently thanking her dear U-556.

''I am sure you all know why we are here tonight.'' Bismarck began simply, folding her arms behind her. ''We are here, because the war – _our _war, against the Royal Navy, is now over.''

A few discontented murmurs resounded in reply. She waited for them to die down before she continued.

''This action was not taken lightly by the High Command. The Sirens have grown to be a threat that outmatches the Royal Navy several times over. Should we have won over the Royals, we would only further damn our world. The Sirens are not a threat any single nation can face alone and win. A single of their elite can handle even the strongest of our fighters, and their overlords exist on a plane of existence near-unfathomable to us. I should know; I faced one of these overlords down. And lost.''

It stung to admit her defeat, especially since it wasn't even a fight. The Siren wasn't even trying to hurt her; if anything she was doing the opposite. She still vividly remembered Observer Alpha looming over her, an invisible pressure crushing down on her as if the Siren was so strong even gravity bent to her will simply with her mere presence.

Shaking off her dark memories, Bismarck continued. ''As of this moment, the Royal Navy are no longer our enemies, nor are the Eagle Union. We are all in this together against the Sirens, not simply to protect our nation, but our world as a whole. For the Sirens do not conquer us with the intent to occupy, but to experiment and toy with us, as if we were mere lab experiments.''

Murmurs echoed, stronger now and filled with displeasure, clearly irritated by the mere thought of the Sirens lording over them.

''I understand that to some, our newfound allies will be hard to accept. We have been fighting them for many years now, after all. I do not blame you for this. I do not expect you to let the past go, nor to forgive those that sunk our allies. Your grudges are your own, and I have no right to interfere with them. However I expect you to work alongside them, no matter how reluctantly, in the name of the greater good.''

''Time moves ever onward.'' Bismarck stated strongly, spending a long second to gaze around the room, everyone listening with rapt attention. ''And we will not be left behind to rust! Sharpen your blades, train your guns and oil your riggings! The Sirens will not hesitate, and so we shall not either! By iron or blood we will emerge victorious, and they shall know the true meaning of war!''

A resounding cry came from the audience, and when she raised a clenched fist, so too did every soul in the room.

The Sirens may be strong. The Sirens may be cunning. The Sirens may be godly.

But they were born of Iron and Blood.

And they would make the Sirens pay for every inch of sea they stole.

X-x-X

The rest of the night passed in pleasant chatter, the mood far lighter than when the night started.

''Surely you jest, _Schwester?_''

Tirpitz chuckled behind her hand. ''I'm afraid not. Your Submarine launched herself off my convoy ship via a Destroyer, skipped across the sea like a stone, and swam after her rigging for a solid three minutes. While I find it reckless, I can't help but be amused, in hindsight.''

Bismarck shook her head in disbelief. ''That girl, honestly...''

The blonde let her gaze wander, drifting over to said Submarine. She was giggling happily and tipping back a glass of pink wine, U-81 rolling her eyes and sipping her own drink, clearly trying to be the sensible one out of the whole group. For someone so usually playful she had suddenly acted more responsible around the time Tirpitz had first arrived. Dimly, she wondered if that had any connection.

As if sensing her gaze U-556 turned towards her, giving her a bright – if slightly drunk – smile and a wave, one Bismarck amusedly returned. The Submarine said something to her pink-haired sister before skipping over to the two Battleships, nearly tripping on the stairs up to her throne. Now that she was closer Bismarck could see how red her face was, more than likely due to alcohol.

''Bismarck~'' U-556 drunkenly greeted, giggling to herself.

Bismarck glanced at her sister, trading an amused look. ''Good evening, my dear. Having fun?''

''Mmhm~!'' The Submarine giddily jumped, nearly stumbling back down the stairs had Tirpitz not pre-emptively laid a hand on her shoulder.

''Perhaps it is time for you to head back.'' Tirpitz remarked amusedly.

Bismarck had to agree with that. ''Yes, I believe that would be wise. It would be a shame to ruin the night with an accident.''

U-556 pouted. ''But I wanna stay until you leave~!''

''Then I shall leave with you now.'' The blonde countered easily.

The Submarine happily bobbed her head at that, prompting Bismarck to rise from her throne. A few glanced at her, but when it was clear she was just leaving they returned to their conversations. Bidding her sister a good night Bismarck walked down the steps, holding a hand out to U-556. The shorter girl blushed cutely and grinned, taking her offered hand and skipping down the steps.

Tirpitz watched them go, smiling lightly. It made her happy to see her sister happy, and mentally she thanked U-556 for everything she had done. Everything she had learned from Bismarck told of a childish girl, but one with an unfaltering loyalty. A loyalty that only deepened when she and Bismarck took their relationship further than merely servant and master, and became lovers.

Shaking her head lightly Tirpitz turned, heading up the stairs curving around behind Bismarck's throne and heading up to the second floor. She nodded briefly at Scharnhorst and Gneisenau as she passed, drifting over to the balcony.

_'Lovers...'_ Tirpitz couldn't help but let her mind wander back to that one word, a pang echoing in her heart.

As someone who spent years of her life in the cold, unforgiving north, she longed for companionship to fill the void in her heart. It was a natural reaction, she knew, but that didn't make the yearning any less visceral. At times it physically pained her, as if her very heart was being ripped apart by the loneliness. Bismarck helped fill that void, and the others in the base unknowingly did too... but she yearned for someone more. Someone to warm her icy heart.

A sigh blew past her pale lips, forming a faint cloud in front of her due to the cold evening air. The temperature had been dropping recently, even though it was only August. Even here, back in her homeland, she couldn't escape the cold.

Leaning on the balcony railing, Tirpitz stared out into the vast ocean. Bismarck had confided in her how dangerous the Sirens truly were, and Tirpitz believed her. Very few could attest to single-handedly defeating Bismarck at her full strength; there was a reason the Royal Navy sent out an entire hunting pack just for her alone. Yet one of the Siren's 'overlords' not only defeated her, but did so without raising a finger. Their mere presence could nearly bring Bismarck to her knees.

''How frightening...'' Tirpitz murmured softly.

''What is?''

The Battleship blinked, glancing over her shoulder. There, standing in the shadow of the archway, was a pink-haired girl in a thigh-length dress. It took Tirpitz a moment to recognise her as U-81, U-556's sister.

''...how powerful the Sirens are.'' Tirpitz said slowly, turning her gaze back to the ocean.

Soft clicks of shoes-on-stone graced her ears as U-81 approached the railing. ''Eh... it doesn't matter how strong they are, we'll win.''

Tirpitz frowned. ''How can you be so certain of that?''

''Because U-556 said so.'' The Submarine's simple answer dumbfounded the taller woman. ''Childish she may be, but she's rarely wrong about things.''

''...that's quite a naïve belief.'' Tirpitz couldn't help but say.

If U-81 was offended, she didn't show it. ''Maybe. But I don't have any reason to doubt her. Even if I do, I have faith in Bismarck, in my sisters, in our fleet. We'll win because we have to. Simple as that.''

The Battleship pondered her words, a light huff passing her lips. ''How strange. Your words almost seem to inspire me.''

''Heh, I've been working on being more leader-like, after all.'' U-81 smugly replied, hopping up onto the railing and swinging her legs over the edge, unafraid of falling.

Tirpitz hummed in acknowledgement, gazing at the pink-haired girl. ''What brings you out here, if I may ask?''

U-81 sighed explosively. ''My sisters. Handling them is like herding cats. Doubly so when they're drunk off champagne and fruit punch. So I pawned them off to Z23.''

''...are you sure that's wise?''

''Nope.'' U-81 smirked unrepentantly, kicking her legs idly.

Silence fell upon them, but it was strangely comfortable, neither in a rush to break it. Tirpitz leaned more on the railing, letting her shoulders relax. It was strange, but the Submarine's naïve confidence was infectious. She couldn't help but believe that they would win. Maybe not today, nor tomorrow, but one day. One day they would rid their seas of the Sirens, and reclaim them as their own.

''What'cha planning on doing? Now that the war with the Royal Navy is done with.''

Tirpitz blinked, pondering the Submarine's words for a long moment. She hadn't thought about that. She was so busy thinking about their war with the Sirens to really think about everyday life. Her mind wandered, trying to think of things she could do to entertain herself during her downtime... and found nothing.

''I'm... not sure.'' The Battleship said slowly, almost hesitantly. ''In the north there was precious little things to do besides patrolling. I'm afraid outside of war, I don't have any hobbies to attend to.''

U-81 seemed genuinely surprised about that. ''Really? Nothing?''

Seeing Tirpitz slowly shake her head, U-81 perked up. ''How about I help you then? We can go down to the next town over, try some stuff, see what interests you? I've been there enough to know my way around; I'm sure there's something you'd like!''

The Submarine extended a hand to her, and almost unconsciously Tirpitz found herself raising her own hand, clasping U-81's smaller hand in her own – a slight smile gracing her face.

''I would be delighted to.''

Slowly, the void inside her icy heart shrunk a little more, the sparks of something foreign setting alight a gentle flame in Tirpitz's heart.

[END]


End file.
